A senior Palestinian official today said he has asked the US, Britain and France to help bring three of their nationals for questioning about the huge leak of confidential documents relating to peace talks in the Middle East.

Chief negotiator Saeb Erekat said the three include a former British intelligence officer, a US employee of al-Jazeera TV and a French citizen. He said he is not accusing them of wrongdoing, but would like them to appear before an investigative committee.

Al-Jazeera this week published excerpts from what it said is a cache of hundreds of documents covering a decade of Israeli-Palestinian negotiations. The Qatar-based Arab satellite station, widely watched in the Arab world, alleges that the Palestinian president, Mahmoud Abbas, secretly made major concessions to Israel.

Abbas and his aides say they are victims of a smear campaign.

The leaks have intensified the bitter rivalry between Abbas and Hamas, the Islamic militant group which wrested the Gaza Strip from the Palestinian president in a violent takeover in 2007.

Yesterday, thousands marched in Gaza in Hamas-led protests, accusing Abbas of being a traitor and burning him in effigy.

Today, hundreds rallied in Gaza City, burning a photo of Abbas and raising a large picture of al-Jazeera's benefactor, the emir of Qatar.

Salah Bardawil, a Hamas legislator, told the crowd that "those traitors and anyone who is thinking of compromising any of our rights" should be put on trial.

In the West Bank, several thousand Fatah supporters chanted slogans against al-Jazeera and in support of Abbas. They also burned photos of two senior Hamas leaders.

Erekat, who frequently meets with Israeli and US officials, features in many of the documents. Palestinian officials have said they believe the documents were leaked by someone in a department he heads, the negotiations support unit.

Erekat told the Associated Press today that the investigation into the leaks is still continuing.

Erekat said he has tried to contact the US citizen, but to no avail. "I am not accusing him of anything. We want to investigate him," he said, adding that he had contacted US diplomats for assistance.

Al-Jazeera officials have been unavailable for comment throughout the week. The French national declined comment when contacted by AP, and the former British intelligence officer said he might discuss the issue at a later time.

Many of the leaked documents detail 2008 negotiations between Abbas and Israel's leader at the time, Ehud Olmert. Those talks were cut short by Israel's three-week war on Hamas-ruled Gaza, launched in late 2008, and mounting corruption allegations against Olmert that eventually forced him out of office.